The carpal tunnel is a space in the palm region of a human hand, with a floor of the carpal tunnel formed by a concave arch of carpal bones covered by wrist ligaments and a roof of the carpal tunnel formed by transverse carpal ligament extending in a transverse direction across the wrist from a base of the thumb to an outer portion of the wrist bones. The carpal tunnel forms a conduit for the median nerve and digital flexor tendons extending from the forearm into the palm.
Carpal tunnel syndrome is a condition where a reduction in the size of the carpal tunnel compresses the median nerve, resulting in pain and/or numbness in the wrist and/or hand. Compression of the median nerve can also result from an increase in the volume of the tissue inside the carpal tunnel or movement of the flexor tendons. Compression of the median nerve can cause pain, numbness or other adverse sensation in the wrist, hand, fingers or thumb that can radiate to the forearm.
Conventional methods to treat early stage carpal tunnel syndrome can include injection of non-steroidal anti-inflammatory drugs, splinting and/or injection of corticosteroid. Surgery to obtain carpal tunnel release is generally recommended after six to seven weeks of conservative treatments when persistent signs of aggravated two point discrimination and an electromyography results indicating diminished nerve conduction velocities.
Carpal tunnel release is a surgical procedure that is commonly performed in the field of hand surgery. Various surgical methods to obtain carpal tunnel release include open, limited incision and endoscopic techniques. Surgery for carpal tunnel release involves a simple incision of the transverse carpal ligament to relieve direct compression on the median nerve in the carpal tunnel. Such surgery seeks to minimize damage to the superficial palmar arch vessels, to avoid incision induced scars, and to avoid injury to nerves, e.g., the palmar cutaneous branch of the median nerve, thenar branch, or median, ulnar and digital nerves. VanDoesburg et al. describe pathologic findings in patients with carpal tunnel syndrome of non-inflammatory fibrosis and thickening of the subsynovial connective tissue, including the transverse carpal ligament. See, VanDoesburg M H, et al., Sonographic Measurements Of Subsynovial Connective Tissue Thickness In Patients With Carpal Tunnel Syndrome, J. Ultrasound Medicine 31:31-36 (2012).